Sarah competes in a long jump competition, Her first jump is 4.25 m.
Her best jump is 12% more than this.
However, her best jump is 15% lower than the winning jump.
Work out the length of the winning jump.

The graph below shows the amount of money left in the school’s desk fund, f, after d desks have been purchased. for each new desk that is purchased, by how much does the amount of money left in the school’s desk fund decrease?

Find the value of x for which abcd must be a parallelogram -9-6x x-30

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?